This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

The term "tipping point" refers to a critical threshold at which a small change can qualitatively alter the state of a system. For example, when temperature reaches 32°F, ice changes into water. There also are "tipping points" in global warming. The best known is the Greenland Ice Sheet, which could begin a slow, irreversible meltdown if global temperature passes a certain threshold.

Last week, climate researchers published a paper that examines Earth systems in danger of passing tipping points due to human activity. They call these "tipping elements", and highlight nine such systems from around the world. They say the greatest threat is to the Arctic, followed by the Greenland Ice Sheet. Here's the list.

Read more »

This post is by Sheryl Canter, an Online Writer and Editorial Manager at Environmental Defense.

It's not just an election year, it's an historic election year. Every news outlet is filled with speculation and commentary. So why is it so quiet here, at Climate 411? How come we don't talk about the election and the candidates?

It's because of our tax status. Environmental Defense is incorporated as a 501c3 charitable organization. This means that donations to us are tax deductible, and we are allowed only limited lobbying and no electioneering whatsoever. Even commenting on candidates' climate change plans could imply that we prefer one over the other and jeopardize our tax status. That's why we talk about policies and not about candidates.

This post is by Sheryl Canter, an Online Writer and Editorial Manager at Environmental Defense.

The U.S. Environmental Protection Agency (EPA) has come out with a neat new calculator that can make sense of all those arbitrary-sounding greenhouse gas numbers.

What does a metric ton of carbon dioxide look like? The calculator shows a dozen different equivalencies, such as 114 gallons of consumed gasoline, 2.3 barrels of oil, or 0.01 acres of forest preserved from deforestation. And it's not limited to metric tons or CO₂. You also can try different amounts and different greenhouse gases.

The EPA developed the calculator to help people in communicating about reduction targets, but it's useful to anyone trying to get a handle on the numbers.

This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

Yesterday, an unusually ferocious winter tornado system killed at least 55 people in five Southern states, and destroyed over a thousand homes and businesses. Usually tornadoes touch down for 20 minutes then come back up, but these were rare "long-track" tornadoes that stayed on the ground for 30 to 50 miles.

Lots of recent research indicates that global warming increases the intensity of hurricanes. Could it also affect tornadoes? It's too early to tell, but scientists are starting to look.

Read more »

This post is by John Balbus, M.D., M.P.H., Chief Health Scientist at Environmental Defense.

On February 3, Parade published a misleading Medical Alert column with the headline "Bright Lights, Bad Headache?" by Dr. Isadore Rosenfeld. It starts with a list of unsubstantiated claims:

As energy-saving fluorescent lightbulbs become standard, new research suggests some dangers: Flickering bulbs have been reported to precipitate migraines or even seizures, though manufacturers say the new models have been improved. Fluorescent light also can aggravate skin rashes in people with lupus, eczema, dermatitis or porphyria.

Environmental Defense could find no published scientific studies demonstrating that compact fluorescent light bulbs (CFLs) trigger migraines or seizures. And unlike older fluorescent tube lights, modern CFLs with electronic ballasts don’t flicker.

Read more »

This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

The results are in for 2007, and it was a warm one. How warm? It depends who you ask. According to NASA, 2007 was the second warmest year on record. NOAA's analysis put it in fifth place. The University of East Anglia's Climatic Research Unit (CRU) ranked it eighth.

The results differ because it's not as straightforward as you might think to take the temperature of the globe. There are many subtleties to consider.

Read more »

This post is by Mark Brownstein, Managing Director of Business Partnerships at Environmental Defense.

A little over a year ago, Environmental Defense, the Natural Resources Defense Council (NRDC), and Ceres sent a letter to the three lead banks financing the TXU deal we helped broker. We said the banks no longer could ignore CO₂ in their investment decisions.

Today we are seeing the culmination of this effort. The three banks - Citigroup, J.P. Morgan Chase, and Morgan Stanley - have announced that they will require utilities seeking financing to prove the new plants would be economically viable under an expected federal cap on greenhouse gas emissions.

This will make it much harder for utilities to build conventional coal plants.

Read more »

This post is by Sheryl Canter, an Online Writer and Editorial Manager at Environmental Defense.

Belkin's Conserve Surge Protector - At the Consumer Electronics Show this month, Belkin showed a new surge protector called Conserve that can shut off six of its eight outlets with a switch, or with a handy remote control (in case you don't like climbing under your desk). Standby or "phantom" power from devices such as TVs, computers, and battery chargers, can account for up to 20 percent of your electric bill. This device could save you money, as well as reduce your carbon footprint.

Eco-Fashion - It used to be only hippies who cared about natural fibers and sustainably produced clothing, but no more. Now top designers have gotten into the act. One company in Denmark, Earth A'Wear, does nothing but.